This invention relates to an electronic scanning apparatus for ultrasonic imaging (which will hereinafter be called "ultrasonic imaging apparatus"), and more particularly to an ultrasonic imaging apparatus of a simpler construction.
An ultrasonic imaging apparatus is used to scan an object linearly or sectorwise by moving an ultrasonic beam while controlling the amplitude and phase of vibrations of arrayed transducers, and thereby take a tomograph of the object.
The construction of a conventional ultrasonic imaging apparatus will now be described with reference to FIG. 1.
Referring to FIG. 1, reference numeral 1 denotes arrayed transducers, 2 a switch unit for selecting a predetermined number of transducers, which determine a transmitting and receiving aperture, from the arrayed transducers, 3A a transmitting driver, 3B an amplifier for receiving signals, 4A, 4B second switch units for switching the data represented by the transmitting and receiving signals, 5A, 5B beam formers for phasing the transmitting and receiving signals, 6 a compressor-detector, and 7 a display.
As generally known, in the conventional ultrasonic imaging apparatus constructed as described above, a predeteremined number of transducers are selected from all of the arrayed transducers 1 by the first switch unit 2, and, the transmitting drivers 3A and the amplifier 3B for receiving signals, the numbers of which drivers and amplifiers are in agreement with that of the transducers to be selected. The second switch units 4A, 4B are connected to the transmitting driver 3A and amplifier 3B for receiving signals, respectively. These second switch units 4A, 4B are adapted to be switched periodically in accordance with the movement of the transmitting and receiving aperture, and capable of simultaneously connecting the transmitting or receiving signals in the two transducers which are symmetrical with each other with respect to the center of the transmitting and receiving aperture. Accordingly, a half of the whole of the transducers of the transmitting and receiving aperture may be phased by the beam formers 5A, 5B.
In the conventional ultrasonic imaging apparatus described above, it is necessary that the transmitting drivers and amplifiers for receiving signals, the numbers of which are in agreement with that of the transducers of the transmitting and receiving aperture, be provided, and that the second switch units and beam formers be provided for transmitting and receiving signals, respectively. This causes the dimensions and manufacturing cost of the apparatus to increase.